If this is your first visit, be sure to
check out the FAQ by clicking the
link above. You may have to register
before you can post: click the register link above to proceed. To start viewing messages,
select the forum that you want to visit from the selection below.

What if someone were to recreate the architecture fairly accurately from a level in any of the official Thief games, but then changed the story/characters/items etc. to fit into the world of TDM?

You can't copyright basic floorplans. Unless it was something really specific, like The Sword, I highly doubt a recreation of original level geometry would be recognizable in a different engine, anyway, so that's likely to be fine.